(a) Field of the Present Invention
The present invention is disclosed by that the capacitive impedance components and the inductive impedance component in series connection are powered by a pulsed power, whereof their inherent series resonance frequency produces a series resonance status with the pulse period of the pulsed power, whereof in series resonance, a bi-directional divided power is formed across at the two ends of the capacitive impedance component or of the inductive impedance component and is rectified by a rectifier device to provide DC power output to drive the unidirectional conducting light emitting diode, or to drive the at least two rectifier devices which are respectively parallel connected across the two ends of the first impedance and second impedance while the AC powers of the first impedance and second impedance are respectively through the said rectifier devices to be converted to DC power output, thereby to drive the unidirectional conducting light emitting diodes individually.
If the high frequency bi-directional power is used in the uni-directional light emitting diode drive circuit in pulsed power series resonance, then its volume and weight can be effectively reduced as well as that the cost can be lowered.
(b) Description of the Prior Art
The conventional light emitting diode drive circuit using AC or DC power source is usually series connected with current limit resistors as the impedance to limit the current to the light emitting diode, whereof the voltage drop of the series connected resistive impedance always result in waste of power and accumulation of heat which are the imperfections.